The present invention relates to an intercranial pressure regulator valve and, more particularly, to a valve for and method of shunting excess cerebrospinal fluid (CSF) from a ventricle in the brain to another location in the patient's body when the pressure differential between the CSF and the other body fluid reaches a predetermined magnitude.
Hydrocephalus is a condition in which the brain is unable to relieve itself of CSF which collects in the ventricles of the brain. Such CSF, thereby, becomes excessive and results in abnormal ventricular size causing a number of adverse physiological effects including compression of the brain tissue, impairment of the blood flow in the brain tissue and of the brain's normal metabolism.
A variety of CSF pressure regulator valves and methods of controlling CSF pressure have been developed in the past which include various forms of check valves, servo valves or combinations thereof. Although these prior valves operate with some degree of success in the treatment of hydrocephalus, difficulty in the operation of such valves may be experienced due to the miniaturization of the valves and the relatively low pressures and volumes with which they must work.
An intercranial pressure regulator valve and method of draining body fluids in accordance with the principles of the present invention minimizes such difficulties in operation. In a valve and method of the present invention, performance is substantially improved in extremely small, miniaturized regulator valves, yet the valves are fully hydraulic in operation. In a regulator valve and method incorporating the principles of the present invention, the body fluid pressures may be accurately regulated and the valve is extremely responsive to minute changes in the pressure of the fluids. In a valve and method incorporating the principles of the present invention, the body fluids act on surfaces of substantial area and on both sides of a movable member or diaphragm so that the valve and method of the present invention is responsive to substantially smaller pressure differentials than the valves and methods of the prior art. In a valve and method of the present invention, the pressures at which response occurs may be rapidly and easily adjusted without interfering with the operation of the valve. In a valve and method incorporating the principles of the present invention, springs may be eliminated and a diaphragm or other movable member which is responsive to pressure variations may, instead, be employed, thereby reducing the number of parts, the possibility of malfunction and other disadvantages which may be associated with such springs.
In one principal aspect of the present invention, a valve for the passage of body fluids from one location in the body to another and the regulation of the pressure of such fluids comprises movable means having first and second surfaces of substantial area thereon. First coupling means communicates the area of the first surface with the fluid from the one location and a second coupling communicates the area of the second surface with the other location. Valve seat means on the movable means is movable therewith and includes a passage for the flow of the fluid from the first to the second surfaces. Valve closure means is positioned on the side of the movable means adjacent the first surface. The valve closure means is engaged by the movable valve seat means to close the passage in response to a first lower pressure differential of the fluid acting on the first and second surfaces, and the movable means and its valve seat means is movable away from the valve closure means to open the passage in response to a second higher pressure differential of the fluid acting on the first and second surfaces.
In another principle aspect of the present invention, the aforementioned movable means is a flexible diaphragm.
In still another principal aspect of the present invention, the aforementioned passage extends through the movable means or diaphragm.
In still another principal aspect of the present invention, the aforementioned valve closure means includes means for stationarily mounting the valve closure means such that the valve seat means moves relative to the valve closure means.
In still another principal aspect of the present invention, the valve closure means includes adjustment means for adjusting the force by which the valve seat means engages the valve closure means.
In still another principal aspect of the present invention, the aforementioned valves drain cerebrospinal fluid (CSF) and the first coupling means includes a catheter for communicating with the tissue in the body from which the CSF is to be drained.
In still another principal aspect of the present invention, the aforementioned valve closure means comprises a substantially spherical ball which is engageable by the valve seat means.
In still another principal aspect of the present invention, a method of draining body fluids from one location in the body to another location to regulate the pressure of the fluid includes communicating the fluids at the one location with a first surface of substantial area on a movable member. A passage which communicates the first surface with a second surface also of substantial area on the movable member is closed when the pressure differential between the surfaces is at a first lower pressure differential by moving the movable member and a valve seat mounted thereon relative to and into engagement with a substantially stationary valve closure means. The passage is opened to communicate the first surface with the second surface when the pressure differential between the surfaces is at a second higher pressure differential and in response to the second higher differential by moving the movable valve closure means to drain the fluids from the one location to the other location.
In still another principle aspect of the present invention, in the last mentioned method, the movable member is a flexible diaphragm and the pressure differentials cause the diaphragm to flex to result in the movement of the movable member and valve seat.
In still another principal aspect of the present invention, the aforementioned methods include adjusting the valve closure means to adjust the force by which the valve seat engages the valve closure means to alter the second higher pressure differential.
In still another principal aspect of the present invention, in the aforementioned methods, the fluid is CSF.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.